Thread protector



Feb. 10, 1953 s. PHILLIPS 2,627,877

THREAD PRoTEcToR Filed May 6, 1950 40 f3 lfella-5 INVENToR.

5TH/WISY Ff/LL/Ps Arnhems-ys Patented Feb. 10, 1953 THREAD PROTECTOR Stanley L. Phillips, Parkview Village, Cleveland,

Ohio, assigner to Wedge Protectors, Inc., Cleveland, Ohio, a corporation of Ohio Application May 6, 1950, Serial No. 160,495

(Cl. 13S-96) 2 Claims. 1

This invention relates to thread protectors i the kind made from sheet metal and adapted to be applied to the ends of pipes, conduits and machine parts to protect the screw threads of such parts against damage from blows or contamination by foreign matter during handling, shipping and storage.

Thread protectors of this kind are usually discarded as scrap material after a single use and this makes it necessary that the protectors be manufactured as economically as possible. There are, however, certain requisites which must be met in such thread protectors and which have heretofore prevented the manufacturing cost from being reduced below a certain minimum.

One of these requisites is a certain rigidity and strength needed to protect the thread against blows and which has heretofore been obtained by selecting the weight or gauge of sheet metal stock which will provide the required rigidity and strength in the protectors made from such sheet metal stock. Another such requisite is that the protector have a relatively smooth and finished shape which is devoid of burrs and sharp edges, such that the protectors and the pipes or machine parts to which they are applied, can be handled safely and without danger of causing personal injury or torn clothing. To provide the protectors with such a smooth and finished shape as heretofore required additional forming and trimming operations which have materially increased the cost of manufacture.

The present invention deals successfully with these problems and provides a novel construction for a sheet metal thread protector which will permit the protector to be manufactured more economically and yet without sacrifice in its strength and rigidity or in the smoothness and regularity of its shape.

Another object of this invention is to provide a novel construction for a thread protector of the sheet metal type, in which a hollow annular rim integrally formed on the outer end of the sheet metal sleeve of the protector provides an annular seat for engagement with the end of the threaded member and also reinforces and stiens the protector so effectively that it can be manufactured from a lighter gauge of sheet metal without any material sacrice in rigidity or strength.

A further object is to provide an improved thread protector of the character mentioned Vin which the hollow annular rim is of a radial width such that the periphery thereof extends beyond the periphery of the threaded member and whichrim periphery has knurling extending therearound to facilitate obtaining a secure grip on the protector for applying the same to the threaded member but more particularly for removing the protector from such threaded member. lStill another object is to provide an improved thread protector of this character in which a packing is connected with the protector by having a holding portion retained in the hollow annular rim and such packing is adapted for sealing engagement with the end of the threaded member to which the protector is applied.

Yet another object is to provide an improved thread protector of the kind above referred to and intended for application to an internally threaded hollow member having an internal chamfer, in which the sheet metal of the sleeve portion of the protector denes an axially inwardly converging annular taper adjacent the hollow annular rim for seating engagement with the internal chamfer of the threaded member.

Other objects and advantages will be apparent in the following detailed description and in the accompanying sheet of drawings in which,

Fig. l is an elevation, with portions in longitudinal section, showing one form of the improved thread protector of the present invention applied to an externally threaded pipe end;

Fig. 2 is an outer end view of the thread protector of Fig. l showing the same in ldetached relation;

Fig. 3 is an elevation, with portions in longitudinal section, showing a thread protector similar to that of Fig. 1 but which includes a packing element;

Fig. 4 is an elevation, with portions in longitudinal section, showing another form of the improved protector applied to an internally threaded member;

Fig. 5 is an elevation, with portions in longitudinal section, showing a thread protector similar to that of Fig. 4 but which includes a packing element; and

Fig. 6 is an elevation with portions in longitudinal section, showing still another form of the improved thread protector applied to an internally threaded member.

In `the embodiment of the invention illustrated in Fig. 1, a, thread protector I Il of the outside type is shown applied to a threaded member, in this instance a pipe end I I, having an external screw thread I2 thereon.

The thread protector i0 comprises a sleeve I3 which has been drawn or otherwise suitably formed from sheet metal and which extends in Asurrounding coaxial or telescoping relation on the pipe end II so as to cover and protect the screw thread I2 thereof. The thread protector I0 also includes a holding means carried by the sleeve I3 and engageable with the thread l2 for retaining the protector on the pipe end il. In this instance, the holding means is an internal helical thread I4 formed on the intermediate portion only of the sleeve I3. The thread I4 comprises a number of continuously connected thread convolutions such as can be formed by a rolling or swaging operation during which metal of the wall of the sleeve I3 is deflected substantially radially inwardly and formed into Substantially V-shaped thread ridges.

The thread protector I0 is applied to the pipe end II and is removed therefrom by a rotary movement during which the protector is screwed onto or ol of the pipe end. The protector I0 is constructed so that it preferably has an axial length somewhat longer than the threaded portion of the pipe and such that when the protector is fully applied it will cover and shield the threaded portion against blows which would be damaging to the thread and vagainst foreign matter of all kinds which :might contaminate or y,

corrode the thread.

As an important feature of the present invention the thread protector I0 is provided at its outer end with a hollow annular bead or rim `I5 which is integrally connected with Vthe sleeve I3 and is substantially radially inwardly oiset therefrom so as to occupy a position in an inwardly overhanging relation such that it will engage the annular end face I5 of the pipe end .II when the protector is screwed onto the thread I2. hollow annular rim I5 is formed by the sheet metal of the outer end of the sleeve I3; such sheet metal being deflected so as to extend in an inwardly offset and reversely curled relation as shown in Fig. l of the drawing. Such deflection of the sheet metal of vthe outer end of the sleeve I3 into this reversely curled .relation to denne the hollow annular rim I5 can be accomplished by any suitable drawing, forming or spinning dies by which sheet metal operations of this kind are accomplished.

The hollow annular rim I5 is dened by integral wall portions of the sheet metal sleeve I3 which include a substantially radially inwardly extending annular wall portion 15a, an axially extending annular wall .portion I'5b and a substantially radially outwardly extending annular Wall portion I5c. These annular wall portions I5a, I 5b and I5c are integrally connected oontinuous portions of the sheet :metal located at the outer end of the sleeve I3 and denne the` above-mentioned inwardly deected and reversely curled portion of the sleeve which denes the annular bead I5. As shown Yin Fig. 1,*the outwardly extending annular portion proaches, but preferably does not engage, the wall defining the main portion of the sleeve I3.

When the thread protector ID is applied to the pipe end Il, the inwardly offset hollow annular rim I5 engages the end face I iof the pipe end y.

and, in cooperation with the thread I4, produces wedged or locked engagement on the pipe end for retaining the protector thereon. The hollow annular rim I5, Vand particularly the outwardly deilected annular portion I5c thereof, will be capable of some springing or yielding when the protector is applied to the pipe end for producing Athis locked effect and also as the result of blows delivered against the outer -end portion of the protector during handling or shipping of the pipe.,

The..

Since the annular rim I5 is hollow and has this limited yielding` or spring characteristic, it will readily absorb such blows or jars and prevent the same from damaging the threaded end of the pipe.

As another feature of this invention the improved thread protector Iil is constructed so that the hollow annular rim i5 will have a radial width such as to locate the inner periphery of the rim at a point inwardly of the inner surface or periphery il of the pipe and this inner periphery of the rim is provided with knurling I8. When the hollow annular rim I5 has such an increased radial width and carries the knurling I8 on its inner periphery, an appropriate tool or a secure hand-grip can be applied to the protector for more easily unscrewing the same from the threaded pipe end II when the protector is to be removed. n

One important advantage resulting from the above described construction for the thread protector IG is that the hollow annular rim I5 reinforces and stiilens the sheet metal sleeve I3 to such an extent that the protector Ii) can be made from a much lighter gauge of sheet metal stock than has heretofore been practical. For example, it is pointed out that when the thread protector Ill is of a size to be applied to a pipe of approximately 2% inch nominal size, it was necessary heretofore to make the protector out of sheet metal stock of I3 gauge. With the improved construction here shown for the protector I, the increased rigidity afforded by the hollow annular rim I5 makes it possible to construct the protector out of sheet metal stock of 16 gauge, or even a lighter gauge, without materially sacrificing any strength or rigidity in the protector. The lighter gauge of sheet metal stock now used can be more easily formed than the heavier gauge heretofore used and therefore results in an advantage in die expense, bot-h as to initial die cost and die maintenance.

Another important advantage resulting from the hollow annular rim I5 is a manufacturing advantage in that a protector of a smooth and regular shape and devoid of dangerous burrs and sharp corners can be made with fewer manufacturing operations. This is possible because during the manufacture of the thread protector Hl the sheet metal at the outer end of the sleeve i3 can usually be formed to its inwardly deflected and reversely curled condition during a single forming operation and, since the extreme annular end of the sleeve I3 is disposed in the nished protector in a position where it will not be engaged by the hands or clothing of the workmen handling the protector or the pipe carrying the same, it will not require any trimming or smoothing operation as has heretofore lbeen necessary to remove or eliminate such dangerous burrs and sharp edges.

Fig. 3 of the drawing shows a thread protector '28 of a construction generally similar to the above described thread protector I0 and applied to the external thread 2I of the pipe end 22. The thread protector 2B comprises a sheet metal sleeve "53 carrying an internal thread 2li, as above explained, for retaining the protector on the pipe-end 22. The protector 233 also includes a radially inwardly oiset hollow annular bead or riin 25 which is formed by the sheet metal of the outer end of the sleeve 23. As in the case of the hollow annular rim I5 described above, the rim 25 is formed by inwardly, axially and outwardly extending continuously connected annular portions a, 25h and 25o which constitute the inwardly and reversely curled end portion of the sleeve 23.

The thread protector of Fig. 3 embodies the additional feature of a packing 26 carried by the outer end of the protector 23 and engageable with the outer end of the pipe 22 when the protector is applied thereto. The packing 23 has a holding portion 2'| which is locked or retained in the annular recess 28 of the hollow rim 25 and also includes a ring portion 29 projecting from the hollow rim and adapted for sealing engagement with the extreme end portion of the pipe 22 or the initial thread convolution 2 la thereof.

The packing 26 may be a ring formed of any material suitable for sealing purposes between the protector and the pipe end such as paper, asbestos or other fibrous material, rubber or rubber-like material, or a soft metal such as brass, copper, or aluminum. This packing ring can be assembled into connected relation with the protector 23 without requiring any additional manufacturing operation, by simply placing the packing ring in a position to have the holding portion 2l thereof engaged and confined in the recess 28 of the hollow rim 25 when the sheet metal of the outer end of the sleeve 23 is deflected into the above described reversely curled relation.

Such deflection of this portion of the sleeve 23 I causes the annular portion 25o to engage the packing ring 23 and press the same against the main wall of the sleeve 23 with the relatively enlarged retaining portion 21 confined or locked in the recess 28.

When the protector 23 has been applied to the pipe end 22 the packing 23 will assist in causing the protector to be securely held on the pipe and will also assist in centering the outer end of the protector on the pipe end. This packing will also serve the purpose of absorbing some of the blows and shocks which are delivered against the outer end of the protector during handling and shipping of the pipe and will form a seal at the outer end of the pipe which will assist in excluding foreign matter which might otherwise corrode or contaminate the thread 2|.

Fig. 4 of the drawing shows a hollow member or pipe iitting 3|, such as a coupling having an internal thread 32 therein, and a thread protec- 5.,

-beyond the outer periphery of the coupling 3| and carries knurling 4| such that this peripheral portion of the rim will be readily engageable by a suitable tool or by hand grasp for conveniently tightening. the thread protector 33 or removing the same from the coupling or other member to which it is applied.

When the hollow annular rim 38 is provided on the protector 33 and has substantially the shape described above, it will be seen that the outer end of the sheet metal sleeve 35 will not require any trimming or smoothing operation such as has tor 33 of the inside type embodying the present invention and applied to this coupling in protective relation to the thread thereof. The coupling 3| is also provided with an inwardly converging annular axial chamfer 34 ladjacent its outer` end nular rim l5 of the above described external thread protector I3, that is to say, the hollow annular rim 33 stiifens and reinforces the protector 33 so that it can be safely constructed from a lighter gauge of sheet metal and this rim is engageable with the annular end face of the coupling 3|. The hollow annular rim 38 extends in a radially outwardly offset or over-hanging relaheretofore been necessary to eliminate dangerous burrs and sharp corners and which additional operation has increased the cost of manufacture. The elimination of such a trimming or smoothing operation is possible because in this improved construction the annular portion 38o in its reversely curled relation, as shown in Fig. 4, occupies a position in which it is not engaged by the hands or clothing of the workmen handling the protector 33, or the coupling or other threaded member to which the protector has been applied.

The above-mentioned inwardly converging axial taper 39, provided on the thread protector 33 between the rim 38 and the helical thread 36 thereof, constitutes another important feature of this protector because it cooperates with the inernal chamfer 34 to produce new results including the centering of the outer end of the protector on the coupling 3|. The axially tapered portion 39 is constructed so that its outer end will provide an annular shoulder or edge 33a of a diameter to wedgingly engage in the internal chamfer 34 when the protector 33 is screwed into the coupling 3| for the distance necessary to cause the hollow annular rim 33 to engage the end face 40 of the coupling. This wedging engagement of the annular 4shoulder or edge 33a not only centers the outer end of the protector in the outer end of the coupling 3| but lforms an annular seal by the .metal-to-metal engagement between the protector and the coupling 'at this point. Such a seal is desirable because it enables the protector to exclude foreign matter from the thread 32 which might otherwise corrode or contaminate such thread.

In Fig. 5 of the drawing a thread protector .43 is shown which is of a construction similar to the thread protector 33 described above and in which the corresponding parts are designated by the same reference characters. The thread protector A3 is used in the same manner and aiords the same advantages as theabove described protector 33. In addition, the thread protector 43 carries a packing 44 at its outer end and which is held in connected relation with theprotector by having a holding portion 44a retained or locked in the annular recess 45 of the hollow annular rim 38. The packing 44 also includes a ring portion Mb which projects from the rim 38 and is engageable with the end face 40 of the coupling 3| `ecc'momically produced because the 7 when the protector isfully applied thereto. The packing 44 can .be constructed of a material, and can bemounted on the rim 38 in substantially the same way, as described above for the packing 2S of Fig. 3.

Fig. 6 of the drawing shows a thread protector 41 which is also similar to the thread protector 33 described above and in which corresponding parts are designated by the same reference characters. The thread protector 41, however, is provided at the outer end thereof with an external annular ange 48 which lies adjacent the axial taper 39 and engages the outer end of the internal chamfer 34 when the protector is applied to the coupling 3 l.

The llange 48 is formed by the extreme end portion of the sheet metal at the outer end of the sleeve 35 and constitutes an integral extension of the inwardly deflected substantially radial v-sheet metal portion 38e. When the protector 4l is applied to the coupling 3| and is tightened to its final position thereon the flange 48 will be wedged into the internal chamfer 34 at the same time that the hollow annular rim 38 is brought into seating engagement with the end face 40 of the coupling. This Wedging of the iiange 48 into the internal chamier 34 will produce a metal-tometal seal between the protector and coupling at this point and will also produce an automatic centering and locked engagement of the outer end of the protector on the coupling.

From the accompanying drawing and foregoing detailed description it will now be understood that this invention provides an improved construction for a thread protector to be used on the threaded end of a pipe, machine part or other member and which protector can be more integral hollow annular rim formed on the outer end of the protector stiffens and reinforces the same so that a lighter gauge of sheet metal can be used. It will also be seen that this hollow annular rim has a springing and yielding action for absorbing blows which might otherwise damage the threaded end of the member and this rim of itself, or assisted by a packing member or a flange extension, also forms a seal with the outapplied and accomplishes a centering and locking cooperation with such outer end by which the protector is held against lateral shifting or accidental unscrewing. Additionally, it will be seen that in the improved protector the hollow annular rim is of a radial width and cariies knurling such that the peripheral edge thereof will extend beyond the periphery of the member to which the protector is applied and will facilitate the application or removal of the protector by the use of a suitable tool or a handgrip. It will be seen, furthermore, that the use of the hollow annular rim at the outer end of the protector not only produces a stronger and more rigid protector from a lighter gauge of sheet metal, but the radially deflected and reversely curled relation of the sheet metal of the outer end of the sleeve which forms this hollow annular rim eliminates the need for trimming-the vsheet metal, or performing other machine operations thereon at this point which have heretofore been necessary to remove dangerous burrs and sharp edges.

Although the improved thread protector of the present invention has been illustrated and described herein to a somewhat detailed extent it will be understood, of course, that the invention isnot to be regarded as being limited correspondingly in scope but includes all changes and modications coming within the spirit of the invention and the language of the claims hereof.

YI-laving thus described my invention, I claim:

l. A thread protector for application to a hollow member having an internal thread and also having an internal annular chamfer at its outer end comprising, a; sheet metal body having a sleeve portion adapted to enter said hollow member, means carried by said sleeve portion and engageable with said thread for holding the protector in connected relation with said member. the sheet metal at the outer end of said sleeve portion extending in an outwardly and reversely curled relation dening a substantially radially outwardly offset hollow annular rim adapted for seating engagement with the outer end of said member, said hollow annular rim carrying an annular flange defined by the extreme end portion of the sheet metal of the body constituting the protector and said iiange extending around said sleeve portion in an axially inwardly converging relation so as to form a tapered annular seat engageable wiih the internal annular chamfer of said member.

2. A thread protector for application to a hollow member having an internal thread and also having an internal annular cham'fer at its outer end comprising, a sheet metal body having a sleeve portion adapted to enter said hollow member, means carried by said sleeve portion and engageable with said thread for holding theprotector in connected relation with said member, the sheet metal at the outer end of said sleeve portion extending in an outwardly and reversely curled relation defining a substantially radially outwardly offset hollow annular rim adapted for seating engagement with the outer end of said member, said hollow annular rim carrying an annular flange defined by the extreme end portion of the sheet metal of the body constituting the protector and said flange extending around said sleeve portion in an axially inwardly converging relation so as t0 form a tapered annular seat engageable with the internal annular chamfer of said member, said hollow annular rim being of a radial width such that its outer periphery projects beyond the outer periphery of said member, and knurling carried vby and extending around said outer periphery of said rim.

STANLEY L. PHILLIPS.

REFERENCES CITED The following references are of record in the iile of this patent:

UNITED STATES PATENTS Number Name Date 676,976 Bossert June 25, 1901 1,640,369 Westerman Aug. 33, 1927 1,847,396 Hochenaver et al. Mar. l, 1932 1,949,431 Osborn Mar. 6, i934 2,098,087 Engstrom Nov, 2, 1937 2,213,430 Irwin et al. Sept. 3, 194i) 2,385,408 Engstrom Sept. 25, 1945 

